1. Field of the Invention
The present invention relates to a substrate processing method in which a processing fluid is used to process an upper surface of a substrate and a gap washing method in which a gap between a body opposite the upper surface of the substrate and an opposing member is washed. Examples of substrates to be processed include semiconductor wafers, substrates for liquid crystal display devices, substrates for plasma displays, substrates for FEDs (field emission displays), substrates for optical disks, substrates for magnetic disks, substrates for magneto-optical disks, substrates for photomasks, ceramic substrates, substrates for solar cells.
2. Description of Related Art
In the manufacturing process of a semiconductor device or a liquid crystal display device, a substrate processing apparatus is used that processes a substrate such as a semiconductor wafer or a glass substrate for liquid crystal display devices. A single substrate processing-type substrate processing apparatus that processes substrates one by one includes, for example, a spin chuck which holds a substrate horizontally and rotates the substrate and a processing liquid supply unit which supplies a processing liquid to the substrate held by the spin chuck, a shielding member which opposes the substrate held by the spin chuck from above and a center axis nozzle which is stored in a central opening formed in a central portion of the shielding member. The shielding member is a member which approximates an upper surface of the substrate to shield the upper surface from a space therearound.
When the substrate is processed with this substrate processing apparatus, for example, in a state where the shielding member and the center axis nozzle are retracted to a retraction position which is largely separated above the substrate, the processing liquid from the processing liquid supply unit is supplied to the upper surface of the substrate. As the processing liquid is supplied to the upper surface of the substrate, a processing liquid mist is produced above the substrate, and the processing liquid mist enters cylindrical gaps, with the result that the processing liquid mist may be adhered to an inner circumferential surface of the shielding member and an outer circumferential surface of the center axis nozzle. Hence, it is necessary to wash the cylindrical gaps.
Japanese Patent Application Publication No. 2010-56218 discloses a method of supplying to a lower surface of a shielding member a washing liquid from a washing liquid nozzle to wash the lower surface of the shielding member.